


All You've Ever Known (Is A Lie)

by SymbioticAntithesis



Series: Tumblr Ficlets [4]
Category: Supernatural
Genre: Canon Typical Violence, Demon possession, Gen, Mentions of hell, Post-Sacrifice, fallen!cas, human!Cas, mentions of torture, post-season 8
Language: English
Status: In-Progress
Published: 2013-07-13
Updated: 2013-07-14
Packaged: 2017-12-19 08:33:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 1,850
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/881690
Author URL: https://archiveofourown.org/users/SymbioticAntithesis/pseuds/SymbioticAntithesis
Summary: <blockquote class="userstuff">
              <p>After the angels fall, Dean has his hands full picking up the pieces of the aftermath.  What he doesn’t expect, however, is a forgotten family member wearing a familiar face.</p><p>Series of ficlets involving demon!Adam possessing Castiel post-season 8.</p><p>Chapters are not chronological.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Inspired by two different posts on tumblr, one saying that they wanted possessed!Cas and the other wanted demon!Adam. So I smooshed the two together for a delightfully angsty premise.

It's been three months since the angels fell, three months since Dean nearly lost his brother –  _again_  – and three months since the last time Dean saw Castiel.  And though Dean never said so aloud, he was worried.  Sam knew.  Kevin knew.  But they never talked about it.

He didn't like the idea of Cas out there by himself,  _human,_ unable to find his way back to them.  Dean had searched the surrounding woods in vain while streaks of fire lit the sky, hoping against hope that Cas would be nearby, despite the gut wrenching feeling that the fallen angel would not be that easy to find.  After all, when was anything easy for them?

Dean had given up after an hour, telling himself that he should focus on what was in front of him first - Sam.  So he had piled Sam into the Impala - and at the last minute decided to take Crowley with them, he could still be useful - and drove off into the relative darkness of the night.

When Dean pulled up in front of the bunker, Kevin came rushing out, concern and fear etched on his features.  "Dean?"

Dean pursed his lips and got out of the car, shaking his head.  He walked around the Impala and opened the passenger door, heaving Sam upright.  "We need a flesh sigil," he jerked his head to the backseat of the Impala, "And a devil's trap at the entrance."  Kevin frowned when he saw Crowley, but he didn't question Dean, simply nodded and did as he was told.

Since then, Dean had been busy with nursing Sam back to health and ensuring that Crowley couldn't escape or harm the three of them in the bunker, though he was sure the dungeon was strong enough to contain him.  Kevin had been helping Dean in any way he could, and contacted Garth and Charlie as per Dean's request.

Charlie had been trying to track where the angels fell but so far she's had little to no success.  She claimed it was because the angels would no longer have a supernatural wavelength or signature since they were all essentially human now.  Dean was practically asking her to find hundreds of humans across the entire world with no knowledge about any of them save for the fact that they were once heavenly beings.

And Dean hated the fact that Charlie was right.  They'd simply have to wait, and Dean didn't like it.  Cas was out there somewhere, powerless - hell, he might not even be in the states.

During those three months, Charlie updated Dean on any possible leads.  There had been a handful of news reports on an influx of vagrants and vagabonds appearing out of nowhere with varying degrees of shock, confusion, and fear.  But none of them were Cas, and for now, only Cas mattered.

Just after the three month mark - maybe only a couple of days – Charlie informed him of demonic activity near Lincoln, Kansas and, being only about an hour and a half drive, Dean decided to check it out.  Especially after Charlie quipped, "It's like they  _want_  to be found."

Sam was still recovering and Dean flat out refused to take him along, and Kevin had already agreed to stay behind to look after the younger Winchester.  But Sam insisted that he not go alone so Dean begrudgingly agreed to have Garth drive out to meet him.

Before Dean set out the next morning, he ensured Sam that he’d be fine and clapped Kevin on the shoulder.  Kevin nodded, face grim, and Dean hopped into the Impala.  He instantly felt a calm wash over him as he sat behind his baby’s wheel, starting the engine.  The rumbling purr put a small smile on his lips, despite all the crap that’s been happening.

The drive to Lincoln was quick and uneventful, and when he arrived, Dean poked around at the sheriff’s office while he waited for Garth’s call.  There had been a couple unexplained deaths and power surges, and on the surface, the city appeared completely normal.

Garth called a few minutes after Dean left the sheriff’s office, saying that he’s spotted some shady characters just north of town.  He confirmed the location before sliding back into the Impala to meet Garth.

It only took fifteen minutes to find Garth’s car and Dean left the engine on idle as he stepped out and greeted the other hunter.

"They’re in the farmhouse down the road," Garth said, pointing to the building a few miles away.

Dean nodded, “How do you know they’re demons?"

Garth gave him a small smile, “They wanted to be found.  They stared right at me and their eyes turned black, in broad daylight too."

Dean sucked in a breath, “They were expecting us."

The other hunter nodded, “It’s a trap, I’m sure of it."

He pursed his lips in thought.  There were two things they could do: one, go in anyway or two, drive away.  And Dean sure as hell didn’t want to do the latter and if they were going to do the former, they’d have to at least have some sort of tactic.  "All right, here’s what we’re going to do …"

And twenty minutes later, three of the four demons were dead and the last was strapped to a chair, confined in a hastily scrawled devil’s trap on the farmhouse floor.  The ease of the battle put Dean’s teeth on edge; he didn’t like it one bit.

"What are you doing here?" Dean asked, standing in front of the demon.

The demon laughed, “Dean Winchester, are you in for a fantastic surprise."

Dean’s eyes narrowed, “Who are you working for?  Crowley?  Abaddon?"

"Crowley is a pathetic excuse for a demon," he spat.  "And Abaddon has gone underground, didn’t you hear?  Too afraid to show her face, because a new and more powerful demon has risen from Hell."

Dean’s eyes widened in shock.  His gaze darted to Garth, and the other hunter had the same expression.  "Who is it?"

"Oh, you’ll see," the demon sneered.  "Very soon."

Dean gripped Ruby’s knife and stepped forward.  Then without warning, he stabbed the demon in the thigh.  The demon screamed in agony, his head thrown back and veins popping in his neck and arms.

"Who is it?!"

The demon glared, “Fuck off."

Dean scowled and yanked the knife out.  Before he could do anything else, however, the doors of the farmhouse flew open.  Dean jumped and turned around, moving to the side of the demon, seeing Garth doing the same on his left.  The afternoon sun streamed in and a figure strode in calmly, a tan trench coat billowing behind him.

"Cas?"

The former angel looked Dean straight in the eye for a few long moments then said, “Hello Dean."

Dean let out a breath, “Son of a bitch, you’re alive."

Cas’ lip twitched, amusement glittering his blue eyes.  "Yes," he said, his gaze falling to the ground.  "I am."  When he looked back up, his eyes were white, and a wicked smile split his lips.

Dean froze, his mind going blank, his heart seizing in his chest.   _Shit._ No, this couldn’t be happening.

Cas was possessed.  He wasn’t possessed by just any demon, either – it was a high-ranking one, on the same level as Lilith.  This scenario hadn’t crossed Dean’s mind in the months after the angels fell, but it should’ve.  Damnit, it should’ve.  Because Cas was human and susceptible to possession, and he would never be able to kill a demon in Castiel’s body.  Ever.  The thought of hurting his friend left a vile taste in his mouth.

"Who are you?" he heard Garth say as he continued to stare in shock.

"Oh, Dean and I go way back," not-Cas said, and Dean could barely focus on his words, too wrapped up in his guilt and disbelief.  He should have looked harder for Cas, should have convinced Cas to stay instead of flying off to Metatron, should have done more to find him.  "In fact, you can practically call us family."

Dean snapped out of his stupor and another wave of guilt and disbelief washed over him.  "Adam?"

And not-Cas grinned even wider, the mirth and sadistic joy looking so incredibly  _wrong_  on Cas’ face.

"Hello, brother."


	2. Chapter 2

**Notes for the Chapter:**

> Warnings for mentions of Hell and torture, and canon typical violence.
> 
> Oh, and guilt. Lots of guilt.

"He’s screaming inside, you know," Adam said conversationally, his grip tightening around Dean’s throat, choking him.  "Telling me to leave you alone, to do anything I want with him and his now-human body - as long as I don’t hurt you."  He scoffed, “But really, where is the fun in having  _this_  vessel and  _you_  at the same time if I don’t take advantage of it?"

"You’re a fucking asshole," Dean managed to wheeze out.

“ _I’m_ the asshole?" he asked, voice hardening.  "That’s rich, coming from you."  Adam released Dean’s neck but punched him hard in the gut making Dean double over in pain.  Before he could recover, Adam backhanded him across the face.  Dean felt blood trickle down the side of his mouth; he must have bit his tongue.

“ _I’m_ the asshole, when  _you’re_  the one who  _left me_  in the pit with Michael and Lucifer.  Who  _forgot_  about me for years.  You remember Hell, don’t you Dean?  You remember Sam after your precious angel pulled him out of the Cage but left me behind?  Imagine something ten times - no, a thousand times - worse."

_Fuck_ , yes he remembered that he decided to bring Sam’s soul back instead of Adam’s - Death had given him a choice, after all.  Then so much shit happened with the Alphas, the Leviathans, and the fucking word of God tablets that the thought of his half brother fell by the wayside.

"Adam, I’m so-"

"Don’t you fucking dare tell me you’re sorry," he growled, glaring at Dean with Cas’ piercing blue eyes.  God, that was so unnerving.  Cas’ body - or was it still technically Jimmy’s? - and Adam possessing him.  It was fucking  _wrong_.

Dean heaved himself forward and clenched his fingers in the tan trench coat.  Adam seized his wrist and twisted, and Dean bit back a curse as he fell to his knees.

"You were in Hell for four months: equivalent to forty years," Adam continued, his grip unrelenting.  "Sam was there for a year and a half: nearly two centuries.  You want to know how long I’ve been in Hell, with Michael and Lucifer tearing me apart only to put me back together to do it all over again?"  Adam threw multiple punches and Dean crumpled the floor, gasping in pain.  His wrist was still clenched in Adam’s hand, his arm at an awkward angle; he was sure his shoulder was dislocated.

"Half a century, Dean."  Adam grabbed him by the collar of his jacket and threw him against the wall behind him.  "And guess what?  It only got worse once you made that deal with Death to pull Sam’s soul out of the pit.  Because then, all they had was me to play with, to torture.

"So don’t you  _dare_ ," Adam hissed, pulling him close so their breaths intermingled.  "Call  _me_  the asshole."

**Author's Note:**

> Will be updated sporadically whenever the mood strikes. Rating may (rather, _will_ ) change for future chapters.


End file.
